Sheet end position regulating device, sheet loader incorporating the sheet end position regulating device, sheet feeding device incorporating the sheet end position regulating device, and image forming apparatus incorporating the sheet end position regulating device

ABSTRACT

A sheet end position regulating device, which is included in an image forming apparatus, includes a first contact body disposed movable on a sheet loading portion on which a sheet is loaded and configured to contact an end portion of the sheet, a fixing body disposed movable between a fixing position at which a position of the first contact body to the sheet loading portion is fixed and a releasing position at which the position of the first contact body is released, and a second contact body disposed movable between a contact position at which the fixing body contacts a contact target portion to regulate movement of the fixing body form the fixing position to the releasing position and a non-contact position at which the fixing body does not contact the contact target portion.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35U.S.C. § 119(a) to Japanese Patent Application No. 2017-248312, filed onDec. 25, 2017, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND Technical Field

This disclosure relates to a sheet end position regulating device, asheet loader incorporating the sheet end position regulating device, asheet feeder incorporating the sheet end position regulating device, andan image forming apparatus incorporating the sheet end positionregulating device.

Related Art

Known sheet end position regulating devices, which regulate the positionof the end portion of a sheet loaded on a sheet loader, includes acontact member that is disposed movable to the sheet loader on which thesheet is loaded to contact the end portion of the sheet and a fixingmember that fixes the contact member to the sheet loader.

As an example of this type of sheet loaders, a known sheet loaderincludes a biasing member such as a coil spring to apply a biasing forceso that the fixing member is located at a fixing position to fix theposition of the contact member to the sheet loader. With thisconfiguration, when an operating force is applied to an operation unitthat operates along with the fixing member, the fixing member moves froma fixing position to a releasing position against the biasing forceapplied by the biasing member, and therefore the contact member becomesmovable to the sheet loader.

SUMMARY

At least one aspect of this disclosure provides a sheet end positionregulating device including a first contact body disposed movable on asheet loading portion on which a sheet is loaded and configured tocontact an end portion of the sheet, a fixing body disposed movablebetween a fixing position at which a position of the first contact bodyto the sheet loading portion is fixed and a releasing position at whichthe position of the first contact body is released, and a second contactbody disposed movable between a contact position at which the fixingbody contacts a contact target portion to regulate movement of thefixing body form the fixing position to the releasing position and anon-contact position at which the fixing body does not contact thecontact target portion.

Further, at least one aspect of this disclosure provides a sheet loaderincluding a sheet loading portion on which a sheet is loaded, and theabove-described sheet end position regulating device disposed movable tothe sheet loading portion and configured to regulate an end portion ofthe sheet loaded on the sheet loading portion.

Further, at least one aspect of this disclosure provides a sheet feederincluding the above-described sheet loader, on which a sheet is loaded,and a sheet feeding body configured to feed the sheet loaded on thesheet loader.

Further, at least one aspect of this disclosure provides an imageforming apparatus including an image forming device configured to forman image on a sheet, and the above-described sheet feeder configured tofeed the sheet toward the image forming device.

Further, at least one aspect of this disclosure provides a sheet endposition regulating device including a first contact body disposedmovable on a sheet loading portion on which a sheet is loaded andconfigured to contact an end portion of the sheet, a fixing bodydisposed movable between a fixing position at which a position of thefirst contact body to the sheet loading portion is fixed and a releasingposition at which the position of the first contact body is released, abiasing body configured to apply a biasing force and bias the firstcontact body, toward an end of the sheet, and a switching bodyconfigured to switch the biasing force applied by the biasing bodybetween a force applying state in which the biasing force of the biasingbody is applied to the end of the sheet via the first contact body and aforce suspending state in which the biasing force of the biasing body isnot applied to the end of the sheet via the first contact body. Theswitching body starts to switch to the force applying state after thefixing body has started to move when the fixing body moves from thereleasing position to the fixing position. The switching body starts toswitch to the force suspending state before the fixing body starts tomove when the fixing body moves from the fixing position to thereleasing position.

Further, at least one aspect of this disclosure provides a sheet loaderincluding a sheet loading portion on which a sheet is loaded, and theabove-described sheet end position regulating device disposed movable tothe sheet loading portion and configured to regulate an end portion ofthe sheet loaded on the sheet loading portion.

Further, at least one aspect of this disclosure provides a sheet feederincluding the above-described sheet loader, on which a sheet is loaded,and a sheet feeding body configured to feed the sheet loaded on thesheet loader.

Further, at least one aspect of this disclosure provides an imageforming apparatus including an image forming device configured to forman image on a sheet, and the above-described sheet feeder configured tofeed the sheet toward the image forming device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

An exemplary embodiment of this disclosure will be described in detailbased on the following figured, wherein:

FIG. 1 is an enlarged perspective view illustrating an end fence in afixed state and parts and components of the end fence other than a fencebody frame;

FIG. 2 is an external perspective view illustrating an image formingapparatus according to an embodiment of this disclosure;

FIG. 3 is a diagram illustrating a schematic configuration of the imageforming apparatus;

FIG. 4 is a side cross-sectional view illustrating a sheet feedingdevice included in the image forming apparatus;

FIG. 5 is a perspective view illustrating the sheet feeding device;

FIG. 6 is a top view illustrating a sheet feed tray provided to thesheet feeding device;

FIG. 7 is a perspective enlarged view illustrating the end fence in thefixed state, viewed from a rear end side of the sheet feed tray;

FIG. 8 is a perspective enlarged view illustrating the end fence in areleased state from the fixed state of FIG. 7, by pressing a releasingbutton;

FIG. 9 is an enlarged perspective view illustrating the end fence ofFIG. 8 and parts and components of the end fence other than the fencebody frame;

FIG. 10 is an enlarged perspective view illustrating the end fence inthe fixed state, viewed from a different angle from the end fence in thefixed state of FIG. 7;

FIG. 11 is an enlarged perspective view illustrating the end fence ofFIG. 10 and parts and components of the end fence other than the fencebody frame;

FIG. 12 is an enlarged perspective view illustrating the end fence inthe released state, viewed from the same angle as the end fence in thereleased state of FIG. 10;

FIG. 13 is an enlarged perspective view illustrating the end fence ofFIG. 12 and parts and components of the end fence other than the fencebody frame;

FIG. 14 is a perspective view illustrating the releasing button;

FIG. 15 is a perspective view illustrating the releasing button, viewedfrom a different angle from the releasing button of FIG. 14;

FIG. 16 is a diagram illustrating an engaging portion of the end fencein the fixed state and a tray housing, viewed from an upstream side of asheet conveying direction;

FIG. 17 is a schematic side view illustrating the sheet feed traywithout any sheet loaded;

FIG. 18 is a schematic side view illustrating the sheet feed tray whenthe end fence is in the released state to the tray housing;

FIG. 19 is a schematic side view illustrating a state in which theposition of a trailing end of the sheet is regulated by the end fence;and

FIG. 20 is a schematic side view illustrating the sheet feed tray in astate in which the end fence has been moved to the upstream side of thesheet conveying direction due to a biasing force applied by a contactplate biasing spring.

DETAILED DESCRIPTION

It will be understood that if an element or layer is referred to asbeing “on”, “against”, “connected to” or “coupled to” another element orlayer, then it can be directly on, against, connected or coupled to theother element or layer, or intervening elements or layers may bepresent. In contrast, if an element is referred to as being “directlyon”, “directly connected to” or “directly coupled to” another element orlayer, then there are no intervening elements or layers present. Likenumbers referred to like elements throughout. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements describes as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, term such as “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors herein interpreted accordingly.

Although the terms first, second, etc. may be used herein to describevarious elements, components, regions, layers and/or sections, it shouldbe understood that these elements, components, regions, layer and/orsections should not be limited by these terms. These terms are used todistinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present disclosure.

The terminology used herein is for describing particular embodiments andexamples and is not intended to be limiting of exemplary embodiments ofthis disclosure. As used herein, the singular forms “a”, “an” and “the”are intended to include the plural forms as well, unless the contextclearly indicates otherwise. It will be further understood that theterms “includes” and/or “including”, when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Descriptions are given, with reference to the accompanying drawings, ofexamples, exemplary embodiments, modification of exemplary embodiments,etc., of an image forming apparatus according to exemplary embodimentsof this disclosure. Elements having the same functions and shapes aredenoted by the same reference numerals throughout the specification andredundant descriptions are omitted. Elements that do not demanddescriptions may be omitted from the drawings as a matter ofconvenience. Reference numerals of elements extracted from the patentpublications are in parentheses so as to be distinguished from those ofexemplary embodiments of this disclosure.

This disclosure is applicable to any image forming apparatus, and isimplemented in the most effective manner in an electrophotographic imageforming apparatus.

In describing preferred embodiments illustrated in the drawings,specific terminology is employed for the sake of clarity. However, thedisclosure of this disclosure is not intended to be limited to thespecific terminology so selected and it is to be understood that eachspecific element includes any and all technical equivalents that havethe same function, operate in a similar manner; and achieve a similarresult.

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, preferredembodiments of this disclosure are described.

Hereinafter, as an embodiment of an image forming apparatus to whichthis disclosure is applied, an electrophotographic image formingapparatus such as a printer that forms an image by anelectrophotographic method will be described with reference to thedrawings.

It is to be noted that identical parts are given identical referencenumerals and redundant descriptions are summarized or omittedaccordingly.

In the following description, the term “image forming apparatus” refersto an image forming apparatus that performs image formation by attachingdeveloper or ink to a medium such as paper, OHP sheet, yarn, fiber,cloth, leather, metal, plastic, glass, wood, ceramics and the like.

Further, it is to be noted that the term “image formation” indicates anaction for providing (i.e., printing) not only an image including textsand figures on a recording medium but also an image not including suchas patterns on a recording medium.

The term “sheet” of the present embodiment includes paper, coated paper,OHP sheet, label paper, film, cloth and the like.

Further, the term “sheet” includes a resin sheet, a protective paper onthe front and back faces, a metal sheet, an electronic circuit boardmaterial subject to metal foil plating such as a copper foil orelectroplating, a special film, a plastic film, a prepreg, an electroniccircuit substrate sheet, and the like. The prepreg is a sheet-likematerial in which carbon fiber or the like is previously impregnatedwith resin. As an example, the prepreg includes a sheet-like reinforcedplastic molding material that is manufactured by, for example,impregnating a thermosetting resin, into which additives such ascurative agent and coloring agent are mixed, in a fibrous reinforcingmaterial such as a carbon fiber or a glass cloth, and then heating ordrying to a semi-cured state.

It is to be noted that the term “sheet” is not limited to indicate apaper sheet but also includes a material which is called as a recordingtarget medium, a recording medium, a recording sheet, or a recordingpaper, and is used to which the developer or ink is attracted. Inaddition, the term “sheet” is not limited to a flexible sheet but isapplicable to a rigid plate-shaped sheet and a relatively thick sheet.

Further, in the following embodiments, size (dimension), material,shape, and relative positions used to describe each of the componentsand units are examples, and the scope of this disclosure is not limitedthereto unless otherwise specified.

In the present embodiment, an electrophotographic printer will bedescribed as an example of an image forming apparatus, but an imageforming apparatus to which this disclosure is applicable is not limitedthereto. Specifically, the image forming apparatus in the presentembodiment is applicable to any of a copier, facsimile machine, printer,printing machine, inkjet recording device, and a multi-functionalapparatus including at least two functions of the copier, facsimilemachine, printer, printing machine, and inkjet recording device.Further, the image forming apparatus according to the present embodimentmay also include an electrophotographic copier provided with an imagereading device.

Further, size (dimension), material, shape, and relative positions usedto describe each of the components and units are examples, and the scopeof this disclosure is not limited thereto unless otherwise specified.

Further, it is to be noted in the following examples that: the term“sheet conveying direction” indicates a direction in which a recordingmedium travels from an upstream side of a sheet conveying path to adownstream side thereof; the term “width direction” indicates adirection basically perpendicular to the sheet conveying direction.

First, a description is given of a basic configuration of the imageforming apparatus 100 according to an embodiment of this disclosure.

FIG. 2 is an external perspective view of an electrophotographic imageforming apparatus 100 (hereinafter simply referred to as the imageforming apparatus 100) according to the embodiment. FIG. 3 is aschematic configuration diagram of the image forming apparatus 100.

The image forming apparatus 100 is a color laser printer.

The image forming apparatus 100 includes an image forming device 400 anda sheet feeding device 300. The image forming device 400 forms an imageon a sheet P that functions as a sheet, specifically, a sheet-likerecording medium. The sheet feeding device 300 feeds the sheet P towardthe image forming device 400.

The image forming device 400 includes four process units 1, that is,process units 1K, 1Y, 1M, and 1C. Suffixes K, Y, M, and C are used toindicate respective colors of the process units 1K, 1Y, 1M, and 1C(e.g., black, yellow, magenta, and cyan toners) of the image formingdevice 400. The process units 1K, 1Y, 1M, and 1C form respective singlecolor images with the respective developers of black, yellow, magenta,and cyan, corresponding to components of color separation of a colorimage.

Each of the process units 1 (i.e., the process units 1K, 1Y, 1M, and 1C)has the configuration identical to each other, except that toners ofdifferent colors (i.e., black (K), yellow (Y), magenta (M), and cyan(C)) are used. Therefore, in the following description, suffixes K, Y,M, and C indicating the color of the toner to be used are appropriatelyomitted and occasionally described in a singular form when theconfiguration and functions of the process units 1K, 1Y, 1M, and 1C areexplained.

The process unit 1 includes a drum-shaped photoconductor 2 (i.e.,drum-shaped photoconductors 2K, 2Y 2M, and 2C) that functions as animage bearer (hereinafter, simply referred to as the “photoconductor2”), a cleaning device 3 (i.e., cleaning devices 3K, 3Y, 3M, and 3C), astatic eliminating device, a charging device 4 (i.e., charging devices4K, 4Y; 4M, and 4C), and a developing device 5 (i.e., developing devices5K, 5Y, 5M, and 5C). Each of the process units 1 is detachablyattachable to an apparatus body of the image forming apparatus 100.Consumable parts of the process unit 1 can be replaced at one time.

An optical writing device 7 is disposed above the four process units 1of the image forming apparatus 100. The optical writing device 7 isconfigured to emit a laser beam from laser diodes disposed therein basedon image data.

A transfer device 15 is disposed below the four process units 1 of theimage forming apparatus 100. The transfer device 15 includes fourprimary transfer rollers 19 (i.e., primary transfer rollers 19K, 19Y,19M, and 19C) and an intermediate transfer belt 16. The primary transferrollers 19K, 19Y, 19M, and 19C correspond to respective toner colors ofthe process units 1K, 1Y, 1M, and 1C. The four primary transfer rollers19K, 19Y, 19M, and 19C are disposed at the respective opposing positionsof the photoconductors 2K, 2Y, 2M, and 2C with the intermediate transferbelt 16 interposed therebetween. The primary transfer rollers 19K, 19Y,19M, and 19C are disposed in contact with an inner circumferentialsurface of the loop of the intermediate transfer belt 16.

The intermediate transfer belt 16 is an endless belt that is entrainedaround the primary transfer rollers 19K, 19Y, 19M, and 19C, a driveroller 18, and a driven roller 17.

A secondary transfer roller 20 is disposed facing the drive roller 18with the intermediate transfer belt 16 interposed therebetween whilepressing an outer circumferential surface of the intermediate transferbelt 16. Thus, a secondary transfer nip region is formed at a positionat which the secondary transfer roller 20 and the intermediate transferbelt 16 contact each other. A belt cleaning device 21 is disposeddownstream from the secondary transfer roller 20 in a belt movingdirection of the intermediate transfer belt 16. A cleaning backup roller21 a is disposed facing the belt cleaning device 21 with theintermediate transfer belt 16 interposed therebetween.

As illustrated in FIG. 2, the sheet feeding device 300 is disposed at alower part of the image forming apparatus 100. The sheet feeding device300 includes a sheet feed tray 30 and a sheet feed roller 47. The sheetfeed tray 30 is a sheet feed tray on which a large number of sheets canbe loaded in a sheet bundle. The sheet feed tray 30 is detachablyattachable to the apparatus body of the image forming apparatus 100 inorder to replenish the sheets P. The sheet feed roller 47 is disposedabove the sheet feed tray 30 in a state in which the sheet feed tray 30is set in the apparatus body of the image forming apparatus 100, asillustrated in FIG. 2. In this state, a sheet P is fed from the sheetfeed tray 30 toward a sheet conveyance passage 31.

A pair of registration rollers 14 is disposed upstream from thesecondary transfer roller 20 in a sheet conveying direction of the sheetP. The pair of registration rollers 14 includes two rollers that forms aregistration nip region therebetween. The sheet P that is fed from thesheet feed tray 30 contacts the registration nip region and stopstemporarily. By stopping the sheet P temporarily at the registration nipregion of the pair of registration rollers 14, the sheet P is sagged atthe leading end thereof.

The sheet P on which the slack is formed is fed out toward the secondarytransfer nip in synchronization at a timing at which a toner image onthe intermediate transfer belt 16 reaches the secondary transfer nipregion. The toner image formed on the intermediate transfer belt 16 istransferred onto the sheet P conveyed from the pair of registrationrollers 14 at the secondary transfer nip region.

A post-transfer sheet conveyance passage 33 is provided above thesecondary transfer nip region and a fixing device 34 is located at aposition close to the upper end of the post-transfer sheet conveyancepassage 33.

The fixing device 34 includes a fixing roller 34 a and a pressure roller34 b. The fixing roller 34 a includes a heat generating source such as ahalogen lamp. The pressure roller 34 b rotates while contacting thefixing roller 34 a with a predetermined pressure.

A post-fixing sheet conveyance passage 35 is provided above the fixingdevice 34 and is branched at a branching portion that is at the upperend of the post-fixing sheet conveyance passage 35 into a sheet outputpassage 36 and a switchback sheet conveyance passage 41.

A switching member 42 is disposed at the branching portion and isswingably driven about a swing shaft 42 a. A pair of sheet outputrollers 37 is disposed at a position close to an opening end of thesheet output passage 36.

A pair of switchback conveying rollers 43 is disposed in the middle ofthe switchback sheet conveyance passage 41. The downstream end of theswitchback sheet conveyance passage 41 in the sheet conveying directionmeets and merges the sheet conveyance passage 31. A sheet output tray 44is formed on top of the image forming apparatus 100 in a shape recessedinwardly.

A waste toner container 10 that functions as a powder container isdisposed detachably attached to the apparatus body of the image formingapparatus 100 and provided between the transfer device 15 and the sheetfeed tray 30.

A transfer cover 8 is disposed above the sheet feed tray 30 and on afront side in a drawing direction of the sheet feed tray 30 (i.e., thetight side in FIG. 3). By opening the transfer cover 8, the inside ofthe image forming apparatus 100 can be inspected. The transfer cover 8includes a bypass sheet feed roller and a bypass sheet feed tray. Asheet loaded on the bypass sheet feed tray is fed by the bypass sheetfeed roller toward the inside of the image forming apparatus 100.

Next, a description is given of basic operations of the image formingapparatus 100, with reference to FIG. 3.

First, the operation of a single-side printing is described.

The sheet feed roller 47 rotates in response to receipt of a sheet feedsignal sent from a controller of the image forming apparatus 100, sothat an uppermost sheet P that is placed on top of the sheet bundle ofsheets P loaded on the sheet feed tray 30 is separated from the othersheets P of the sheet bundle and is conveyed toward the sheet conveyancepassage 31.

When the leading end of the sheet P fed by the sheet feed roller 47reaches the registration nip region of the pair of registration rollers14, the sheet P forms the slack and temporarily stops.

When the sheet P is fed from the bypass sheet feed tray, the sheets P ofthe sheet bundle loaded on the bypass sheet feed tray are fed one by onestarting from the uppermost sheet P placed on top of the sheet bundle bythe bypass sheet feed roller. Then, the sheet P passes part of theswitchback sheet conveyance passage 41 to be conveyed to theregistration nip region of the pair of registration rollers 14 and stopstemporarily. The subsequent operations are the same operations as thesheet feeding operations from the sheet feed tray 30.

In the image forming device 400, the charging device 4 of the processunit 1 uniformly charges the surface of the photoconductor 2 to highpotential.

The optical writing device 7 emits a laser light beam L based on imagedata to the photoconductor 2 having the charged surface. As the opticalwriting device 7 irradiates the surface of the photoconductor 2, thepotential in the irradiated area on the surface of the photoconductor 2decreases to form an electrostatic latent image.

The developing device 5 supplies toner supplied from a toner bottle 6(i.e., toner bottles 6K, 6Y, 6M, and 6C) to the surface of thephotoconductor 2 on which the electrostatic latent image is formed, sothat a toner image of each color is formed (developed) on the surface ofthe photoconductor 2. The toner image formed on the photoconductor 2 istransferred onto the intermediate transfer belt 16 by the primarytransfer roller 19.

After the intermediate transfer process, residual toner remaining on thesurface of the photoconductor 2 is removed by the cleaning device 3. Theremoved residual toner is conveyed by a waste toner conveying unit to becollected to the waste toner container 10. Residual charge remaining onthe surface of the photoconductor 2 after removal of the residual tonerby the cleaning device 3 is electrically discharged and removed by thestatic eliminator.

In the process units 1 (i.e., the process units 1K, 1Y, 1M, and 1C) ofeach color, toner images are formed on the surfaces of thephotoconductors 2 (i.e., the photoconductors 2K, 2Y, 2M, and 2C) of therespective colors through the above-described processes, and the tonerimages of the respective colors are transferred and overlapped oneanother onto the intermediate transfer belt 16.

After the respective toner images of the respective colors aretransferred and overlapped on cone another, onto the intermediatetransfer belt 16, when the composite toner image reaches the secondarytransfer nip region, the toner image is transferred onto the sheet Pthat is fed from the pair of registration rollers 14 by the secondarytransfer roller 20.

The sheet P onto which the toner image is transferred is conveyed to thefixing device 34 through the post-transfer sheet conveyance passage 33.When the sheet P is conveyed to the fixing device 34, an unfixed tonerimage formed on the sheet P is fixed to the sheet P by application ofheat and pressure. The sheet P having the fixed toner image is conveyedfrom the fixing device 34 to the post-fixing sheet conveyance passage35.

The sheet P conveyed from the fixing device 34 is conveyed to the sheetoutput passage 36 via the post-fixing sheet conveyance passage 35. Thepair of sheet output rollers 37 holds the sheet P that is conveyed tothe sheet output passage 36 and rotates to output the sheet P to thesheet output tray 44. After performing the above-described operations,the single-side printing operation is completed.

Next, a description is given of basic operations of a duplex ordouble-sided printing.

Similar to the single-side printing operation, the sheet P is conveyedfrom the fixing device 34 to the sheet output passage 36.

Then, when the duplex printing operation is performed, the pair of sheetoutput rollers 37 is driven and rotated to convey part of the sheet P tothe outside of the apparatus body of the image forming apparatus IOC.When the trailing end of the sheet P passes through the sheet outputpassage 36, the switching member 42 swings about the swing shaft 42 a asindicated by a broken line in FIG. 3, and then the upper end of thepost-fixing sheet conveyance passage 35 is closed. Then, at thesubstantially same time as the closure of the upper end of thepost-fixing sheet conveyance passage 35, the pair of sheet outputrollers 37 rotates in a direction opposite the sheet conveying directionto discharge the sheet P to the outside of the apparatus body of theimage forming apparatus 100, so that the sheet P is conveyed to theswitchback sheet conveyance passage 41.

When the trailing end of the sheet P passes the position of theswitching member 42, the switching member 42 swings about the swingshaft 42 a as indicated by a solid line of FIG. 3, and then the upperend of the post-fixing sheet conveyance passage 35 is opened to guidethe sheet P that has passed through the post-fixing sheet conveyancepassage 35 to the sheet output passage 36.

The sheet P fed to the switchback sheet conveyance passage 41 passes thepair of switchback conveying rollers 43 and reaches the pair ofregistration rollers 14. Similar to the one side of the sheet P isperformed, the sheet P having reached the pair of registration rollers14 is conveyed to the secondary transfer nip region in synchronizationwith the timing at which the toner image formed on the intermediatetransfer belt 16 reaches the secondary transfer nip region. Thereafter,similar to the operation of the single-side printing, the toner image istransferred onto the sheet P in the secondary transfer nip region and isfixed to the sheet P in the fixing device 34, and the sheet P is outputto the sheet output tray 44. After performing the above-describedoperations, the duplex printing operation is completed.

After the toner image formed on the intermediate transfer belt 16 hasbeen transferred onto the sheet P, residual toner remains on theintermediate transfer belt 16. The residual toner is removed from theintermediate transfer belt 16 by the belt cleaning device 21. Theresidual toner removed from the intermediate transfer belt 16 isconveyed to the waste toner container 10 by the waste toner conveyingunit and collected in the waste toner container 10.

Next, a description is given of the sheet feeding device 300, withreference to FIGS. 4 and 5.

FIG. 4 is a side cross-sectional view illustrating the sheet feedingdevice 300 included in the image forming apparatus 100. FIG. 5 is aperspective view illustrating the sheet feeding device 300. FIG. 4illustrates a state in which a front panel 104 is removed from the sheetteed tray 30. FIG. 6 is a top view illustrating the sheet feed tray 30provided to the sheet feeding device 300.

The sheet feeding device 300 is a sheet feeding device that employs aseparation pad.

The sheet feed roller 47 illustrated in FIGS. 4 and 5 is disposed on theside of the apparatus body of the image forming apparatus 100. Further,the sheet feed tray 30 includes a bottom plate 46 and a receiving table49.

The sheet feed tray 30 includes a tray front portion 101 and a tray rearportion 102 that form a tray housing 301 having a bottom face 301 a thatfunctions as a sheet loading portion on which the sheet P is loaded. Thetray rear portion 102 is movable to the tray front portion 101 in adirection parallel to the sheet conveying direction (in a directionindicated by arrow “α” in FIG. 5) and is changeable in the size in thesheet conveying direction of the sheet feed tray 30. An end fence 60that contacts the trailing end of the sheet P in the sheet conveyingdirection and regulates the position of the trailing end of the sheet P.The tray rear portion 102 includes a rail groove 110 that extends in adirection parallel to the sheet conveying direction and the lower partof the end fence 60 (i.e., an end fence engaging portion 62 that isdescribed below) engages with the rail groove 110. By engaging with therail groove 110, the end fence 60 is slidable in the direction parallelto the sheet conveying direction along the rail groove 110. Accordingly,the rail groove 110 functions as a guide to guide the end fence 60 in apredetermined direction (e.g., an X-axis direction).

Since the size of the sheet feed tray 30 in the sheet conveyingdirection is changeable, the sheets having different sizes in the sheetconveying direction are stored in the sheet feed tray 30 while thetrailing end of each of the sheets P having different sizes in the sheetconveying direction is reregulated by the end fence 60.

In the sheet feed tray 30, a right side fence 105 and a left side fence106, which are lateral position fixing members, are disposed on the trayfront portion 101 to be slidable in a direction perpendicular to thesheet conveying direction. In the sheet feed tray 30, the position inthe width direction of the sheet P contained in the sheet feed tray 30is regulated by the right side fence 105 and the left side fence 106,and the position of the trailing end of the sheet P is regulated by theend fence 60. Accordingly, the position of the sheet P in the sheet feedtray 30 is regulated.

As illustrated in FIG. 5, a right lever 130 and a left lever 131 arerotatably (swingably) attached to the tray front portion 101. Therespective upper ends of two bottom plate springs 132 are attached tothe right lever 130 and the left lever 131. The lower ends of the twobottom plate springs 132 are attached (hooked) to the bottom plate 46.

The sheet feed roller 47 is prevented from rotating by the sheet feedroller shaft 50 and a D-shaped cut portion or a pin and is supported bythe apparatus body of the image forming apparatus 100 via a bearing.

The sheet feed roller shaft 50 is extended in a vertical direction tothe drawing sheet of FIG. 4 (hereinafter, referred to as a widthdirection). A drive gear is mounted on a shaft end of the sheet feedroller shaft 50.

The drive gear is coupled to a drive source such as a motor via a driveconnecting member such as a plurality of idler gears, clutches, orsolenoids. Then, a driving force is transmitted from the drive source tothe sheet feed roller shaft 50, and the sheet feed roller 47 rotates ina counterclockwise direction.

By controlling the connecting time of the above-described driveconnecting member and the stop time of the drive source, the sheet feedroller 47 operates intermittently at a predetermined timing.

The sheet feed roller 47 has a surface layer including rubber materialof high coefficient of friction, such that a predetermined conveyingforce is applied to the sheet P. Then, the sheet P is fed by controllingthe connecting time of the drive connecting member and the stop time ofthe drive source.

The dimension of the sheet feed roller 47 are, for example, a diameterof 36 mm and a width of 45 mm. An appropriate size of the sheet feedroller 47 is selected according to the type of the sheet P that is to behandled by the sheet feeding device 300 and the space within the sheetfeeding device 300.

The bottom plate 46 of the sheet feed tray 30 is rotatably supported bya bottom plate rotary shaft 51 that is provided to the sheet feed tray30. The bottom plate 46 is constantly biased upwardly by the two bottomplate springs 132, with the respective upper ends of the two bottomplate springs 132 being fixed to the right lever 130 and the left lever131.

The tray housing 301 includes the bottom face 301 a that functions as asheet loader on which the sheet P is loaded.

When the sheet P is stored in the sheet feed tray 30, the sheet feedtray 30 is pulled out from the apparatus body of the image formingapparatus 100 and the sheet P is loaded on the bottom face 301 a. Atthis time, the leading end of the sheet P in the sheet conveyingdirection is held by the upper face of the bottom plate 46.

When the sheet feed tray 30 with the sheet P is loaded thereon isinserted into the apparatus body of the image forming apparatus 100, theright lever 130 and the left lever 131 are lifted upwardly and held by alever guide provided to the apparatus body of the image formingapparatus 100. With this operation, the respective upper ends of the twobottom plate springs 132 respectively mounted on the right lever 130 andthe left lever 131 are lifted upwardly, and the bottom plate springs 132are extended, so that the bottom plate 46 is lifted upwardly by thebiasing force of the extended bottom plate springs 132. Accordingly, theupper face of the sheet P that is pushed up to the bottom plate 46 ispressed and contacted to the sheet feed roller 47 that is attached tothe apparatus body of the image forming apparatus 100.

As the sheet bundle of sheets P is contained in the sheet feed tray 30and the sheet feed tray 30 is inserted into the apparatus body of theimage forming apparatus 100, the uppermost sheet P contacts the sheetfeed roller 47. By the frictional force generated between the sheet Pand the sheet feed roller 47, the conveying force is applied when thesheet feed roller 47 rotates, and the sheet P is conveyed in a directionto the right side of FIG. 4 (that is, a direction indicated by “α” inFIGS. 5 and 6).

A pad that is a pad member of high coefficient of friction is providedto the receiving table 49. The pad forms a separating portion at whichthe uppermost sheet is separated from the sheets P other than theuppermost sheet P by blocking movement of the sheets P other than theuppermost sheet P in the sheet conveying direction by the pad, so thatthe uppermost sheet P alone is conveyed. When the sheet P is conveyedalong with rotation of the sheet feed roller 47, the uppermost sheet isseparated from the other sheets P at the separating portion.Accordingly, the uppermost sheet P alone is separated and conveyedtoward the downstream side from the separating portion in the sheetconveying direction by the sheet feed roller 47.

As illustrated in FIG. 4, a bottom plate pad 52 that is a pad member ofhigh coefficient of friction is disposed at the leading end of thebottom plate 46 in the sheet conveying direction. The bottom plate pad52 applies a constant load to a lowermost sheet P of the sheet bundleloaded on the sheet feed tray 30. With this configuration, when thesheet bundle of sheets P is loaded on the sheet feed tray 30, thelowermost sheet P is prevented from being conveyed together with asecond lowermost sheet P, in other words, multifeeding is prevented.

Next, a description is given of the end fence 60.

FIG. 7 is an enlarged perspective view illustrating the end fence 60 inthe fixed state to the tray housing 301, viewed from the rear end sideof the sheet feed tray 30.

The end fence 60 includes a fence body frame 61, a fixing claw 80, and atrailing end contact plate 90. The fixing claw 80 functions as a fixingbody to fix the fence body frame 61 to the tray housing 301. Thetrailing end contact plate 90 contacts the trailing end of the sheet Pthat is loaded on the sheet feed tray 30. FIG. 1 is an enlargedperspective view illustrating parts of the end fence 60 of FIG. 7, otherthan the fence body frame 61. In other words, the fence body frame 61 isnot illustrated in the end fence 60 of FIG. 1.

The fixing claw 80 fixes the end fence 60 at an arbitrary position onthe rail groove 110. By so doing, the position of the end fence 60 withrespect to the bottom face 301 a is fixed, so that the position of thetrailing end contact plate 90 of the end fence 60 to the bottom face 301a is fixed. The trailing end contact plate 90 contacts the trailing endof the sheet in a state in which the position of the trailing endcontact plate 90 to the bottom face 301 a is fixed by the fixing claw80. Accordingly, the trailing end contact plate 90 includes a functionto regulate the position of the trailing end of the sheet P and afunction to press the trailing end of the sheet P toward the downstreamside in the sheet conveying direction.

FIG. 8 is a perspective enlarged view illustrating the end fence 60,viewed from the same angle in FIG. 7, in a released state with respectto the tray housing 301 by pressing a releasing button 70 of the endfence 60 of FIG. 7. FIG. 9 is an enlarged perspective view illustratingparts of the end fence 60 of FIG. 8, other than the fence body frame 61.

FIG. 10 is an enlarged perspective view illustrating the end fence 60 inthe fixed state of FIG. 7, viewed from a different angle from FIG. 7.FIG. 11 is an enlarged perspective view illustrating parts of the endfence 60 of FIG. 10, other than the fence body frame 61.

FIG. 12 is an enlarged perspective view illustrating the end fence 60 inthe released state of FIG. 8, viewed from the same angle as FIG. 10.FIG. 13 is an enlarged perspective view illustrating parts of the endfence 60 of FIG. 12, other than the fence body frame 61.

The end fence 60 is provided with the releasing button 70. The releasingbutton 70 is pressed in a direction indicated by arrow A in FIGS. 1 and7, is slidably moved to the fence body frame 61, and releases the endfence 60 from the fixing claw 80.

The releasing button 70 is held to be slidable in the width direction(i.e., a Y-axis direction in the drawings) to the fence body frame 61and the relative movement of the releasing button 70 to the otherdirections is regulated and prevented by the shape of the fence bodyframe 61.

The end fence 60 includes a releasing button biasing spring 71 thatapplies a biasing force to the releasing button 70 in a directionopposite the pressing direction (i.e., a direction indicated by arrow Bin FIGS. 1 and 7). One end (i.e., the right end in FIGS. 1 and 7) of thereleasing button biasing spring 71 contacts the side face of thereleasing button 70 and the other end of the releasing button biasingspring 71 contacts a button biasing spring contact member 72 that isfixed to the fence body frame 61.

As illustrated in FIG. 1, in a state in which the releasing button 70 isnot pressed, the releasing button 70 is biased by the releasing buttonbiasing spring 71 in the direction indicated by arrow B in FIG. 1, and abutton side contact portion 79 that is part of the releasing button 70contacts the side face of the fixing claw 80. The fixing claw 80 isregulated from moving in the Y-axis direction to the fence body frame61, and therefore, when the releasing button 70 that is biased by thereleasing button biasing spring 71 contacts the side face of the fixingclaw 80, the releasing button 70 in the Y-axis direction is positioned.

FIG. 14 is a perspective view illustrating the releasing button 70. FIG.15 is a perspective view illustrating the releasing button 70, viewedfrom a different angle from FIG. 14.

The releasing button 70 includes a button control unit 77 that ispressed to release the fixing claw 80. In addition, the releasing button70 includes a releasing slope 73 and a fixing slide plane 78. Thereleasing slope 73 is inclined such that the negative Y-axis directionis higher than the other axis directions in FIGS. 14 and 15. The fixingslide plane 78 is parallel to a plane X-Y.

As illustrated in FIGS. 1 and 7 through 13, the fixing claw 80 is heldto be slidable in the vertical direction with respect to the fence bodyframe 61 and is biased to the fence body frame 61 by a fixing clawbiasing spring 81 to the fence body frame 61 toward the lower direction(i.e., the negative Z-axis direction).

As illustrated in FIGS. 7 and 10, in the fixed state, a fixing engagingportion 85 that is a lower end of the fixing claw 80 is projected moredownwardly than the lower face of the fence body frame 61. As describedabove, the position of the fixing claw 80 in a state in which the fixingengaging portion 85 is projected more downwardly than the lower face ofthe fence body frame 61 and is engaged with a rack gear 250, which isdescribed below, is referred to as a “fixing position”.

Further, as illustrated in FIGS. 8 and 12, in the released state inwhich the fixing claw 80 is released, the fixing engaging portion 85 ofthe fixing claw 80 is located more upwardly than the lower face of thefence body frame 61 and is recessed from the lower face of the fencebody frame 61. As described above, the position of the fixing claw 80 ina state in which the fixing engaging portion 85 is located more upwardlythan the lower face of the fence body frame 61 and is disengaged fromthe rack gear 250 is referred to as a “releasing position”.

As illustrated in FIGS. 1 and 11, in the fixed state, the fixing slideplane 78 of the releasing button 70 is located at a fixing claw openingportion 84 that is formed in the upper portion of the fixing claw 80. Inthe fixed state, the fixing claw 80 is biased in the downward direction,and therefore the lower face that forms the fixing claw upper endportion 83 forming an upper end of the fixing claw opening portion 84(hereinafter, referred to as the “back face of the fixing claw upper endportion 83”) contacts the fixing slide plane 78. Accordingly, the fixingclaw 80 in the vertical direction is positioned.

As the releasing button 70 in the fixed state is pressed in a directionindicated by arrow A in the drawing and is slid in the positive Y-axisdirection, the position at which the back face of the fixing claw upperend portion 83 contacts slides on the fixing slide plane 78 and reachesthe releasing slope 73. Further, as the releasing button 70 slides inthe positive Y-axis direction, the fixing claw upper end portion 83moves upwardly along the releasing slope 73. As described above, thefixing claw 80 is lifted against the biasing force of the fixing clawbiasing spring 81 and, as illustrated in FIGS. 8 and 12, the state ischanged to the released state in which the fixing engaging portion 85 ofthe fixing claw 80 is recessed upwardly to the lower face of the fencebody frame 61.

In the present embodiment, the fixing claw 80 is biased downwardly bythe fixing claw biasing spring 81. However, the configuration is notlimited thereto. For example, the fixing claw biasing spring 81 may notbe provided and the fixing claw 80 may be moved downwardly by the ownweight. Even in the configuration in which the fixing claw 80 is moveddownwardly by the own weight, a fixing claw contact portion 74 contactsthe fixing claw upper end portion 83 in a state in which the fixing claw80 is located at the fixing position, and therefore the fixed state ismaintained. However, backlash or an error in motion occurs in theconfiguration without the fixing claw biasing spring 81. Therefore, itis desired that the fixing claw biasing spring 81 is provided in orderto eliminate backlash.

FIG. 16 is a diagram illustrating an engaging portion of the end fence60 in the fixed state and the bottom face 301 a, viewed from theupstream side of the sheet conveying direction.

As illustrated in FIG. 16, the rack gear 250 is fixedly mounted on thebottom face 301 a of the sheet feed tray 30. The rack gear 250 functionsas a loader side engaging portion at which the rack gear 250 is engagedwith the fixing engaging portion 85 of the fixing claw 80.

FIG. 17 is a schematic side view illustrating the sheet feed tray 30before the sheet P is loaded thereon. The end fence 60 in FIG. 17 is inthe fixed state to the tray housing 301. FIG. 18 is a schematic sideview illustrating the sheet feed tray 30 when the end fence 60 is in thereleased state to the tray housing 301. FIG. 19 is a schematic side viewillustrating the sheet feed tray 30 in a state in which the position ofthe trailing end of the sheet P is regulated by the end fence 60.

The tray housing 301 includes the tray front portion 101 and the trayrear portion 102 and functions as a sheet loading portion on which thesheet P is loaded to be conveyed toward the image forming device 400that is a sheet conveyance target. The end fence 60 is a trailing endfixing device that is movable in a direction along the sheet conveyingdirection to the tray housing 301 (i.e., in the X-axis direction in thedrawing) and that regulates the position of the trailing end of thesheet P in the sheet conveying direction.

The end fence 60 includes the L-shaped fence body frame 61 having theend fence engaging portion 62 at the lower part of the fence body frame61. The end fence engaging portion 62 at the lower part of the fencebody frame 61 is engaged with the rail groove 110 (see FIGS. 5, 6, and16) mounted on the tray housing 301 and forms a large part of the outershape of the end fence 60. According to the configuration in which thefence body frame 61 is engaged with the rail groove 110, the fence bodyframe 61 is movable along the sheet conveying direction relative to thetray housing 301 and is regulated from moving to the vertical directionand the width direction (in a direction perpendicular to the drawingsheet of FIG. 17).

The fixing claw 80 and the fixing claw biasing swing 81 are attached tothe fence body frame 61 and moves in a moving direction (i.e., theX-axis direction) together with the fence body frame 61.

The fixing claw 80 is slidable in the vertical direction (i.e., theZ-axis direction in the drawing) to the fence body frame 61, and therelative movement in the other directions is regulated due to the shapeof the fence body frame 61. The upper end of the fixing claw biasingspring 81 contacts the fence body frame 61 and the lower end of thefixing claw biasing spring 81 contacts the fixing claw 80. By so doing,the fixing claw biasing spring 81 biases the fixing claw 80 in thedownward direction relative to the fence body frame 61. The leading endof the fixing claw 80 (i.e., the fixing engaging portion 85) biased bythe fixing claw biasing spring 81 is engaged with the rack gear 250.Therefore, the positional relation of the tray housing 301 to which therack gear 250 and the fence body frame 61 to which the fixing claw 80 isattached is fixed. Accordingly, the position of the end fence 60 withrespect to the tray housing 301 is fixed, and therefore the position ofthe trailing end contact plate 90 to the bottom face 301 a is fixed.

When the releasing button 70 is pressed in a direction indicated byarrow A in FIG. 7 to the end fence 60 in the state illustrated in FIG.17, the releasing button 70 slides in the positive Y-axis direction, andtherefore the fixing claw 80 moves to the upward direction against thebiasing force of the fixing claw biasing spring 81. According to thismovement of the fixing claw 80, the fixing claw 80 is disengaged fromthe rack gear 250, and the end fence 60 is released from the trayhousing 301 to change to the state illustrated in FIG. 18. Therefore,the end fence 60 becomes movable in the left and right directions (i.e.,the X-axis direction) in FIG. 18.

When moving the end fence 60, the apparatus body side handle 63 of thefence body frame 61 illustrated in FIG. 7 and the releasing button 70are pinched (for example, by the fingers of a user), so that thereleasing button 70 slides in the positive Y-axis direction to the fencebody frame 61. As a result, the fixing claw 80 slides in the upwarddirection to be disengaged from the rack gear 250, and thereby releasingthe end fence 60. With the apparatus body side handle 63 of the fencebody frame 61 and the releasing button 70 being pinched by the fingersof a user as described above, the end fence 60 is slid to apredetermined position that corresponds to the size of the sheet P to beset, and then the fingers are released from the apparatus body sidehandle 63 and the releasing button 70. Accordingly, the fixing claw 80moves in the downward direction due to the biasing force of the fixingclaw biasing spring 81, and the fixing claw 80 is engaged with the rackgear 250 to change to the state illustrated in FIG. 17. Consequently,the end fence 60 is located at the predetermined position.

The interval of the position at which the end fence 60 is fixed isdetermined based on the pitch of a gear of the rack gear 250. Byreducing the pitch interval, the end fence 60 is moved by a small pitch(e.g., 1 mm intervals). By moving the end fence 60 by a small pitch,regardless of the standard size sheet P such as an A4 size sheet and anA5 size sheet, the end fence 60 is fixed at a position that correspondsto a non-standard size sheet P.

As illustrated in FIGS. 1, 9, 11, 13, and 17 through 19, the end fence60 includes the trailing end contact plate 90 and the contact platebiasing spring 91. The trailing end contact plate 90 presses the sheet Ploaded on the tray housing 301 in the sheet conveying direction. Thecontact plate biasing spring 91 biases the trailing end contact plate90. The trailing end contact plate 90 is assembled to be rotatable abouta contact plate rotary shaft 92 disposed at the upper end of thetrailing end contact plate 90, in a direction indicated by arrow D inFIG. 17 to the fence body frame 61. In other words, the fence body frame61 rotatably supports the trailing end contact plate 90. The upstreamside end of the contact plate biasing spring 91 in the sheet conveyingdirection (i.e., the left side in FIG. 17) contacts the fence body frame61 and the downstream side end of the contact plate biasing spring 91 inthe sheet conveying direction (i.e., the right side in FIG. 17) contactsthe trailing end contact plate 90. Accordingly, the trailing end contactplate 90 is biased such that the lower end of the trailing end contactplate 90 moves toward the downstream side of the sheet conveyingdirection (i.e., the right side in FIG. 17) to the fence body frame 61,and the trailing end contact plate 90 swings or rotates in a directionindicated by arrow D1 in FIG. 17.

When the sheet bundle of sheets P is loaded on the sheet feed tray 30 inFIG. 17, the bottom plate 46 is pressed by the sheet bundle of sheets Pand the downstream side portion of the bottom plate 46 in the sheetconveying direction is lowered. Consequently, as illustrated in FIG. 19,the upper face of the bottom plate 46 becomes substantially horizontal(i.e., the plane X-Y). Further, the trailing end contact plate 90 isalso pressed by the sheet bundle of sheets P, and the lower end of thetrailing end contact plate 90 is rotated in a direction indicated byarrow D2 in FIG. 17 so as to move to the upstream side of the sheetconveying direction. Consequently, the contact plate biasing spring 91is compressed, as illustrated in FIG. 19. At this time, the biasingforce of the contact plate biasing spring 91 is applied to the trailingend contact plate 90 that is in contact with the trailing end of thesheet P, so that the trailing end contact plate 90 presses the sheetbundle of sheets P loaded on the sheet feed tray 30 toward thedownstream side of the sheet conveying direction.

As the (set) number of sheets P of the sheet bundle decreases accordingto the feeding of the sheets P, the force of the sheet P to press thetrailing end contact plate 90 decreases. Therefore, the lower end of thetrailing end contact plate 90 moves to the downstream side of the sheetconveying direction to a position at which the biasing force of thecontact plate biasing spring 91 to bias the trailing end contact plate90 and the pressing force of the sheet P to press the trailing endcontact plate 90 are balanced. Then, the position of the trailing end ofthe sheet P that is regulated by the trailing end contact plate 90 movesto the downstream side of the sheet conveying direction.

As described above, the sheet P is lifted in the upward direction by thebottom plate 46 and is fed by the sheet feed roller 47. At this time,the positional relation of the position of the leading end of the sheetP and the separating portion is significantly determined and theposition of the leading end of the sheet P may need to be set and heldat the identical position regardless of the set number of sheets P.

In the sheet feed tray 30 according to the present embodiment, as thebottom plate 46 is rotated about the bottom plate rotary shaft 51 tolift the downstream side end of the bottom plate 46 in the sheetconveying direction, the downstream side end of the sheet P in the sheetconveying direction (i.e., the leading end side of the sheet P) islifted in the upward direction. In the configuration in which the bottomplate 46 is rotated as described above, when the trailing end of thesheet P is located at a constant position regardless of the set numberof sheets P, the position of the leading end of the sheet P variesdepending on the set number of sheets P. If the position of the leadingend of the sheet P varies and comes out from a target range, it islikely that defects such as paper jam and curling at the leading end ofthe sheet P occur.

By contrast, in the sheet feed tray 30 according to the presentembodiment, the lower end of the trailing end contact plate 90 of theend fence 60 moves in the sheet conveying direction according to the setnumber of sheets P, as described above. Therefore, the trailing endcontact plate 90 presses the sheet P when the set number of sheets Pisrelatively small, so that the fixing position of the trailing end of thesheet P is located closer to the downstream side of the sheet conveyingdirection when compared with the case in which the set number of sheetsP is relatively large. Accordingly, the position of the leading end ofthe sheet P is assigned as the predetermined position at which the sheetP is appropriately fed by the sheet feed roller 47.

Therefore, the position of the leading end of the sheet P to theseparating portion becomes stable, and therefore the sheet feedingdevice 300 can feed the sheet Pin a stable manner.

Further, in the image forming apparatus 100 including the sheet feedingdevice 300 that feeds the sheet P in a stable manner, the timing to feedthe sheet P to the secondary transfer nip region becomes stable, andtherefore defects such as positional deviation of an image to be formedis prevented. Accordingly, the image is formed in the stable manner.

As illustrated in FIG. 16, the end fence 60 includes a resistanceprojection member 89 and a projection member pressing spring 88. Theresistance projection member 89 functions as a released movement fixingdevice to regulate movement of the end fence 60 when the fixing claw 80is released. The projection member pressing spring 88 biases theresistance projection member 89 in the downward direction. Theresistance projection member 89 is movable in the vertical directionthat is a direction to contact and separate a plate portion 251 (i.e., afriction board) that is mounted on the bottom face 301 a of the trayhousing 301 to the end fence 60. The resistance projection member 89 ispressed in the downward direction by the projection member pressingspring 88. According to this pressing of the resistance projectionmember 89, the resistance projection member 89 contacts the plateportion 251, thereby generating a resistant force to the relativemovement of the end fence 60 and the tray housing 301 according to afriction load generated between the resistance projection member 89 thatis biased by the projection member pressing spring 88 and the plateportion 251.

Accordingly, when the releasing button 70 is pressed to change to thereleased state, the end fence 60 is prevented from sweeping orpowerfully moving to the tray housing 301.

As illustrated in FIGS. 1, 7 through 13, and 16, the fixing claw 80 andthe resistance projection member 89 are aligned along the widthdirection of the end fence 60 (i.e., the left and right direction inFIG. 16).

Further, as illustrated in FIG. 16, the plate portion 251 of the bottomface 301 a includes a V-shaped groove 252 at a position that correspondsto the sheet P of a standard size (i.e., the position corresponding to“B6” in FIG. 16).

By providing the V-shaped groove 252 at the position corresponding tothe standard size sheet P, when the end fence 60 that moves on thebottom face 301 a reaches the position corresponding to the standardsize of the sheet P, the resistance projection member 89 falls in theV-shaped groove 252 and stops with a click sound. Due to the soundgenerated when the resistance projection member 89 falls in the V-shapedgroove 252, it is easily recognized that the end fence 60 is located atthe position corresponding to the sheet P of the standard size, andtherefore the operability to change the position of the end fence 60 isenhanced.

Next, a description is given of the end fence 60 according to thepresent embodiment.

As illustrated in FIG. 1, the releasing button 70 that is provided tothe end fence 60 includes a fixing claw contact portion 74 to which thefixing claw upper end portion 83 of the fixing claw 80 in the fixedstate is attached. As described above, the releasing button 70 isregulated from moving to the fence body frame 61 in a direction otherthan the Y-axis direction, and therefore the position of the releasingbutton 70 in the vertical direction is regulated. When the fixing clawupper end portion 83 of the fixing claw 80 contacts a fixing clawcontacting face 74 f that is the lower face of the fixing claw contactportion 74 of the releasing button 70, the fixing claw 80 is restrainedfrom moving to the upward direction to the fence body frame 61.According to this configuration, the fixing claw 80 is prevented frommoving from the fixing position to the releasing position. As describedabove, the releasing button 70 has a function as a contact body tocontact the fixing claw 80 and regulate the fixing claw 80 thatfunctions as a fixing body from moving from the fixing position to thereleasing position.

The end fence 60 according to the present embodiment biases the fixingclaw 80 in the direction in which the fixing engaging portion 85 and therack gear 250 are engaged with each other by the fixing claw biasingspring 81. Even in the configuration without a contact body thatcontacts the fixing claw 80, the fixing claw 80 may be restrained frommoving from the fixing position to the releasing position by the biasingforce of the fixing claw biasing spring 81, However, in a case in whichthe sheet feed tray 30 is attached to the apparatus body of the imageforming apparatus 100 powerfully, a large amount of impact is applied tothe sheet feed tray 30, and therefore a force in the upward direction isapplied to the fixing claw 80. When the force in the upward direction isgreater than the biasing force of the fixing claw biasing spring 81, thefixing claw 80 moves in the upward direction. Consequently, the fixingengaging portion 85 and the rack gear 250 are disengaged from each otherto change to the released state. When any force is applied in thereleased state, the end fence 60 moves on the bottom face 301 a, andtherefore the trailing end of the sheet P cannot be regulated at thedesired fixing position.

Further, similar to the end fence 60 according to the presentembodiment, in the configuration in which the trailing end contact plate90 presses the trailing end of the sheet P, when the end fence 60 isreleased unintentionally while the sheet bundle of sheets P are loadedon the sheet feed tray 30 as illustrated in FIG. 19, the end fence 60may easily move on the bottom face 301 a. This defect is caused for thefollowing reasons.

Specifically, in a state in which the set number of sheets P isrelatively small or in which no sheet P is set, the lower end of thetrailing end contact plate 90 has completely moved to the downstreamside in the sheet conveying direction, as illustrated in FIG. 17, andtherefore the length of the contact plate biasing spring 91 issubstantially a natural length. In this state, the contact plate biasingspring 91 does not apply a force by which the contact plate biasingspring 91 presses the fence body frame 61 to the upstream side of thesheet conveying direction. Therefore, even when any force is applied tothe fixing claw 80 to change to the released state, it is unlikely thatthe end fence 60 moves.

By contrast, as illustrated in FIG. 19, when the set number of sheets isrelatively, large, the lower end of the trailing end contact plate 90 ispressed by the sheet bundle of sheets P to move to the upstream side ofthe sheet conveying direction, and therefore the contact plate biasingspring 91 is compressed. In this state, a biasing force by which thedownstream end of the sheet conveying direction of the contact platebiasing spring 91 contacts and presses the trailing end contact plate 90to which the downstream end of the sheet conveying direction of thecontact plate biasing spring 91 is applied. Then, the trailing endcontact plate 90 contacts the trailing end of the sheet bundle of sheetsP, and the leading end of the sheet bundle of sheets P contacts a wallof the tray housing 301 on the downstream side of the sheet conveyingdirection. Therefore, the biasing force is applied to bias the fencebody frame 61 to which the end of the compressed contact plate biasingspring 91 on the upstream side of the sheet conveying direction contactsto the upstream side of the sheet conveying direction.

In a state in which the biasing force is being applied to the fence bodyframe 61, a relatively large impact is applied to the sheet feed tray30, and a force is likely to be applied to cause the fixing claw 80 tomove in the upward direction. In such a case, the end fence 60 isreleased while the biasing force to bias the fence body frame 61 to theupstream side of the sheet conveying direction is applied. Therefore, asillustrated in FIG. 20, the end fence 60 is moved to the upstream sideof the sheet conveying direction due to the biasing force of the contactplate biasing spring 91.

When the end fence 60 is moved to the upstream side of the sheetconveying direction, a force to press the sheet P in the sheet conveyingdirection at the trailing end contact plate 90 is reduced or theposition of the trailing end contact plate 90 is moved to the upstreamside of the sheet conveying direction. Consequently, the leading end ofthe sheet P is not pushed to the predetermined position, and a gap orspace is generated between the leading end of the sheet P and the wallof the tray housing 301 on the downstream side of the sheet conveyingdirection, resulting in performance of an unstable sheet feedingoperation. Therefore, defects such as curling at the leading end of thesheet P and paper jam occur easily.

In order to address the above-described defects, in the sheet feed tray30 according to the present embodiment, the releasing button 70 includesthe fixing claw contact portion 74 to function as a contact body. As thereleasing button 70 contacts the fixing claw 80, the fixing claw 80 isrestrained from moving from the fixing position to the releasingposition at an unintentional timing, and therefore the end fence 60 isprevented from moving. Accordingly, the end fence 60 is prevented frommoving to the direction opposite the sheet conveying direction at anunintentional timing due to application of a relatively large impact tothe sheet feed tray 30.

The releasing button 70 of the end fence 60 according to the presentembodiment includes the releasing slope 73 that causes the fixing claw80 to move from the fixing position to the releasing position and thefixing claw contact portion 74 to contact the fixing claw upper endportion 83 of the fixing claw 80. Then, the releasing slope 73 causesthe fixing claw 80 to move from the fixing position to the releasingposition along with movement of the fixing claw contact portion 74 froma contact position at which the fixing claw contact portion 74 contactsthe fixing claw 80 to a non-contact position at which the fixing clawcontact portion 74 does not contact the fixing claw 80. As describedabove, the releasing button 70 has a function as a contact body and afunction as a releasing body.

More specifically, as the releasing button 70 is pressed to the endfence 60 in the fixed state, the releasing button 70 slides in thepositive Y-axis direction to a position at which the fixing clawcontacting face 74 f of the fixing claw contact portion 74 does notcontact the fixing claw upper end portion 83. Accordingly, the fixingclaw 80 comes to be movable in the upward direction but is biased by thefixing claw biasing spring 81. Therefore, the back face of the fixingclaw upper end portion 83 contacts the fixing slide plane 78. Further,as the releasing button 70 is pressed to slide in the positive Y-axisdirection, the contact position to which the back face of the fixingclaw upper end portion 83 contacts is moved from the fixing slide plane78 to the releasing slope 73. Accordingly, the fixing claw upper endportion 83 is pressed upwardly along the releasing slope 73, and thefixing claw 80 is moved in the upward direction against the biasingforce of the fixing claw biasing spring 81, and the fixing claw 80 ismoved from the fixing position to the releasing position.

Further, when a user releases the finger from the releasing button 70 inthe pressed state, the releasing button 70 slides in the negative Y-axisdirection as indicated by arrow A′ in the drawing, due to the biasingforce of the releasing button biasing spring 71. At this time, thefixing claw upper end portion 83, the back face of which contacts thereleasing slope 73 due to the biasing force of the fixing claw biasingspring 81, is moved downwardly along the releasing slope 73.Consequently, the fixing claw 80 is lowered to the fixing position. Asthe releasing button 70 further slides in the negative Y-axis direction,the fixing claw upper end portion 83 contacts the fixing slide plane 78,and the fixing claw contacting face 74 f of the fixing claw contactportion 74 is moved to the position to contact the fixing claw upper endportion 83. Accordingly, the fixing claw contact portion 74 of thereleasing button 70 that functions as a contact body contacts the fixingclaw upper end portion 83, so that the movement of the fixing claw 80 tothe releasing position is regulated, which is a contact state.

As described above, the end fence 60 performs, along with one operationto press the releasing button 70, an operation to cancel the contactstate and another operation to move the fixing claw 80 from the fixingposition to the releasing position. Further, along with one operation torelease the releasing button 70, the end fence 60 performs an operationto move the fixing claw 80 from the releasing position to the fixingposition and another operation to change the state to the contact state.Accordingly, the fixing claw 80 is prevented from moving to thereleasing position at an unintentional timing, and therefore theoperability is enhanced.

The operation to change the state from the contact state and theoperation to move the fixing claw 80 from the fixing position to thereleasing position may be performed separately. Further, the operationto move the fixing claw 80 from the releasing position to the fixingposition and the operation to change the state to the contact state maybe performed separately. However, by performing two operations alongwith one operation, the operability can be enhanced. Further, byperforming the operation to change the state to the contact state alongwith the operation to move the fixing claw 80 from the releasingposition to the fixing position, the state is changed to the contactstate without fail after the end fence 60 is moved.

In the end fence 60, when the fixing claw 80 is at the fixing position,the movement of the fixing claw 80 to the releasing position isregulated by the fixing claw contact portion 74 of the releasing button70 that functions as a contact body. Then, immediately before the fixingclaw 80 is moved to the releasing position by the releasing slope 73 ofthe releasing button 70 that includes a function as a releasing body,the fixing claw contact portion 74 of the releasing button 70 is movedto a non-contact position at which the fixing claw contact portion 74 ofthe releasing button 70 does not contact the fixing claw 80.Accordingly, it is prevented that the fixing claw 80 moves to thereleasing position at the unintentional timing immediately before thefixing claw 80 is moved to the releasing position by the releasing body.

When the releasing button 70 is moved to the contact position, thefixing claw upper end portion 83 of the fixing claw 80 and the fixingclaw contact portion 74 of the releasing button 70 contact to eachother. By so doing, the releasing button 70 prevents the fixing claw 80from moving from the fixing position to the releasing position.According to this operation, it is prevented that the fixing claw 80 islifted upwardly.

In the present embodiment, when the releasing button 70 is located atthe contact position, the fixing claw upper end portion 83 and thefixing claw contact portion 74 continuously abut (contact) to eachother. However, if the position of the fixing claw 80 can be maintainedin the fixing position, while the fixing claw upper end portion 83 andthe fixing claw contact portion 74 are disposed apart from each otherwith a predetermined gap (backlash), the fixing claw upper end portion83 and the fixing claw contact portion 74 may contact to each other forthe first time when the fixing claw upper end portion 83 is moved in thevertical direction. In such a configuration, when a user operates(moves) the sheet feed tray 30 in a state in which the releasing button70 is moved to the contact position, it is likely that the fixing claw80 moves in the vertical direction by the predetermined gap (backlash)after receiving an impact by movement of the sheet feed tray 30.However, the fixing claw 80 moves in the vertical direction within arange in which the fixing claw 80 is maintained at the fixing position,in other words, within a range in which the fixing engaging portion 85does not climb over the rack gear 250. Therefore, the fixing of the endfence 60 by the fixing claw 80 is not released by mistake. Therefore, itis prevented that the position of the end fence 60 on the bottom face301 a changes at an unintentional timing.

As illustrated in FIG. 18, when the end fence 60 according to thepresent embodiment is in a state in which the lower end of the trailingend contact plate 90 is regulated from moving to the downstream side ofthe sheet conveying direction (i.e., the right side of FIG. 18) from thepredetermined position by the biasing force of the contact plate biasingspring 91. This state is a force suspending state in which the biasingforce of the contact plate biasing spring 91 is not applied to thetrailing end of the sheet P via the trailing end contact plate 90.

By contrast, as illustrated in FIGS. 17 and 19, in the fixed state, thelower end of the trailing end contact plate 90 is movable to thedownstream side of the sheet conveying direction (i.e., the right sideof FIG. 17) from the predetermined position by the biasing force of thecontact plate biasing spring 91. This state is a force applying state inwhich the biasing force of the contact plate biasing spring 91 isapplied to the trailing end of the sheet P via the trailing end contactplate 90.

The predetermined position is a position at which the right face of acontact plate hooking face 94 (i.e., an inner face having a hook shape)and the left face of a thickness varying portion 76 (i.e., a surface ofa move and stop switching slope 75) contact to each other and thetrailing end contact plate 90 is not rotated any further to the rightdirection, as illustrated in FIG. 18. In the state of FIG. 17 (a firststate), the trailing end contact plate 90 is rotatable to move to theright direction from the predetermined position. In the state of FIG. 18(a second state), the trailing end contact plate 90 is regulated fromrotating and moving to the right direction from the predeterminedposition.

The end fence 60 includes the move and stop switching slope 75 on thereleasing button 70. The move and stop switching slope 75 functions as aswitching body to switch a state in which movement of the trailing endcontact plate 90 is regulated by the biasing force and a state in whichthe trailing end contact plate 90 is movable due to the biasing force.

As illustrated in FIG. 14, the releasing button 70 includes thethickness varying portion 76 at which the thickness in the X-axisdirection continuously changes from a thickness “d1” to a thickness “d2”depending on the position of the releasing button 70 in the Y-axisdirection (d1<d2). The move and stop switching slope 75 that is inclinedto project toward the negative X-axis direction is formed as the face ofthe thickness varying portion 76 on the negative X-axis side is locatedto the negative Y-axis direction.

By contrast, as illustrated in FIGS. 1, 7 through 12, and 7 through 19,the trailing end contact plate 90 includes the contact plate hookingface 94 on an opposite side face to the side to contact the trailing endof the sheet P. The contact plate hooking face 94 is hooked to thethickness varying portion 76. The contact plate hooking face 94 contactsthe move and stop switching slope 75 on the hook-shaped inner face.

In the fixed state, a relatively thin portion of the thickness varyingportion 76, that is, a portion having a smaller amount of projection ofthe move and stop switching slope 75 to the negative X-axis direction isopposed to the contact plate hooking face 94. In the above-describedfixed state, the trailing end contact plate 90 is rotatable in thedirection indicated by arrow D1 in FIG. 17 to the position to which theinner face of the contact plate hooking face 94 contacts the move andstop switching slope 75, due to the biasing force of the contact platebiasing spring 91.

In this fixed state, as the sheet bundle of sheets P is loaded on thesheet feed tray 30 and the lower end of the trailing end contact plate90 pressed by the sheet bundle is moved to the upstream side of thesheet conveying direction, the contact plate hooking face 94 is moved tothe upstream side of the sheet conveying direction (i.e., the negativeX-axis direction). According to this movement of the contact platehooking face 94, the contact plate hooking face 94 separates from themove and stop switching slope 75, as illustrated in FIG. 19.

When the releasing button 70 in the fixed state is pressed and slid tothe positive Y-axis direction, the portion facing the contact platehooking face 94 on the thickness varying portion 76 is slid in theX-axis direction to a portion having a greater amount of thickness.According to this slide of the portion facing the contact plate hookingface 94, the contact plate hooking face 94 is moved in the negativeX-axis direction along the move and stop switching slope 75, and thetrailing end contact plate 90 is rotated in a direction indicated byarrow D2 in FIG. 17 against the biasing force of the contact platebiasing spring 91.

When the releasing button 70 slides in the positive Y-axis directionuntil the state is changed to the released state, the thickness of thethickness varying portion 76 at a portion that is opposed to the contactplate hooking face 94 corresponds to a thickness “d2”. At this time, thebiasing force of the contact plate biasing spring 91 is applied to thetrailing end contact plate 90. However, since the contact plate hookingface 94 and the move and stop switching slope 75 contact to each other,the movement of the trailing end contact plate 90 due to the biasingforce of the contact plate biasing spring 91 is regulated. Then, asillustrated in FIG. 18, the trailing end contact plate 90 is notprojected to the fence body frame 61. Therefore, even when the sheetbundle of sheets P is loaded on the sheet feed tray 30, the trailing endcontact plate 90 does not press the trailing end of the sheet bundle ofsheets P.

As a user releases the finger from the releasing button 70 in thereleased state, the releasing button 70 slides in the negative Y-axisdirection due to the biasing force of the releasing button biasingspring 71. Consequently, the portion of the thickness varying portion 76facing the contact plate hooking face 94 slides in the X-axis directiontoward the thin portion. Accordingly, the contact plate biasing spring91 is movable in the positive X-axis direction along the move and stopswitching slope 75, and the trailing end contact plate 90 is rotatablein a direction indicated by arrow D1 in FIG. 17 due to the biasing forceof the contact plate biasing swing 91.

As described above, with the configuration of the end fence 60 accordingto the present embodiment, the releasing button 70 is slid in the Y-axisdirection. Consequently, a contact position of the move and stopswitching slope 75 to which the contact plate hooking face 94 contactschanges. Due to the change of the contact position, the state in whichthe trailing end contact plate 90 is movable due to the biasing forceand the state in which the trailing end contact plate 90 is regulatedfrom moving are switched. Accordingly, the move and stop switching slope75 has a function as a switching body.

As described above, when the releasing button 70 of the end fence 60 inthe fixed state is pressed in the negative X-axis direction to changethe state to the released state, the trailing end contact plate 90 islowered to the upstream side of the sheet conveying direction (i.e., thenegative X-axis direction). Accordingly, when the end fence 60 in thereleased state contacts the trailing end of the sheet bundle of sheets Ploaded on the sheet feed tray 30, the trailing end contact plate 90 ischanged to a closed state. In this state, the visibility of the setposition of the end fence 60 with respect to the trailing end of thesheet P is enhanced and, as illustrated in FIG. 19, the sheet bundle ofsheets P and the end fence 60 are set to the correct positional relationeasily. Therefore, erroneous setting of the sheet bundle of sheets P isprevented.

By contrast, in a case in a state in which no mechanism to lower thetrailing end contact plate 90 is not provided, it is likely that a statein which the trailing end contact plate 90 contacts the sheet P whilethe trailing end contact plate 90 is open due to the biasing force ofthe contact plate biasing spring 91, as illustrated in FIG. 20, ismisunderstood as the correct positional relation. As illustrated in FIG.20, the positional relation is not correct, the position of the sheet Pin the sheet feed tray 30 is not fixed, which is likely to cause nosheet feeding. The end fence 60 according to the present embodimentprevents the sheet P from being set in the sheet feed tray 30 at anincorrect positional relation. Therefore, the position of the sheet P inthe sheet feed tray 30 is fixed, and no sheet feeding is prevented.

In addition, the move and stop switching slope 75 switches the state ofthe trailing end contact plate 90 between a state in which the trailingend contact plate 90 is movable along with movement of the fixing claw80 along the releasing slope 73 and a state in which the trailing endcontact plate 90 is regulated from moving. By pushing the releasingbutton 70 to the end fence 60 in the fixed state, which is a state inwhich the trailing end contact plate 90 is movable, the releasing button70 slides in the positive Y-axis direction, and the fixing claw 80 ismoved from the fixing position to the releasing position along thereleasing slope 73. At this time, the contact plate hooking face 94 ismoved in the negative X-axis direction along the move and stop switchingslope 75, and the trailing end contact plate 90 is rotated in thedirection indicated by arrow D2 in FIG. 17 against the biasing force ofthe contact plate biasing spring 91. Consequently, the trailing endcontact plate 90 is regulated from moving.

In addition, when the user releases the finger from the releasing button70 in the pressed state while the end fence 60 is in the released state,the releasing button 70 slides in the negative Y-axis direction due tothe biasing force of the releasing button biasing spring 71.

At this time, the fixing claw 80 is lowered along the releasing slope 73to the fixing position. Further, when the releasing button 70 slides inthe negative Y-axis direction, the releasing button 70 is slid in astate in which the fixing claw 80 contacts the fixing slide plane 78,and the state is changed to the fixed state.

Along with this operation to change the state to the fixed state, theportion of the move and stop switching slope 75 at which the move andstop switching slope 75 is opposed to the contact plate hooking face 94slides to the negative X-axis direction toward the portion having asmaller amount of projection. Then, the contact plate hooking face 94 ismovable in the positive X-axis direction to the position to contact themove and stop switching slope 75. That is, the trailing end contactplate 90 is rotatable in the direction indicated by arrow D1 in FIG. 17due to the biasing force of the contact plate biasing spring 91.

As described above, the end fence 60 performs an operation to move thefixing claw 80 from the fixing position to the releasing position andanother operation to switch from a movable state in which the trailingend contact plate 90 is movable to a regulated state in which thetrailing end contact plate 90 is regulated from moving, along with theoperation to press the releasing button 70. Further, the end fence 60also performs an operation to move the fixing claw 80 from the releasingposition to the fixing position and another operation to switch from theregulated state in which the trailing end contact plate 90 is regulatedfrom moving to the movable state in which the trailing end contact plate90 is movable, along with the operation to release the releasing button70. Therefore, the operability is enhanced according to theconfiguration in which the trailing end contact plate 90 is biased bythe contact plate biasing spring 91 and the trailing end contact plate90 is regulated from moving so as not to be projected to the fence bodyframe 61.

It is to be noted that the operation to switch the movable state inwhich the trailing end contact plate 90 is movable and the regulatedstate in which the trailing end contact plate 90 is regulated frommoving and the operation to move the fixing claw 80 between the fixingposition and the releasing position may be performed by differentoperations. However, the operability is enhanced by performing twodifferent operations along with one operation.

The end fence 60 according to the present embodiment has theconfiguration in which, when a user releases the finger from thereleasing button 70 in the released state to cancel the pressure, thetrailing end contact plate 90 has completely projected to the fence bodyframe 61 after the fixing claw 80 is moved from the releasing positionto the fixing position.

This state is made due to the following configuration.

Specifically, while the releasing button 70 is sliding from the releasedstate to the fixed state, the portion of the fixing claw upper endportion 83 to which the back face of the fixing claw upper end portion83 contacts slides on the releasing slope 73, and then slides on thefixing slide plane 78. At this time, when the portion to which the backface of the fixing claw upper end portion 83 contacts reaches the lowerend of the releasing slope 73, the fixing claw 80 is located at thefixing position. Thereafter, while the portion to which the back face ofthe fixing claw upper end portion 83 contacts is sliding on the fixingslide plane 78, the fixing claw 80 remains at the fixing position.

By contrast, the contact plate hooking face 94 remains in contact withthe move and stop switching slope 75 even while the portion to which theback face of the fixing claw upper end portion 83 contacts is sliding onthe fixing slide plane 78. Therefore, even after the fixing claw 80 hasreached the fixing position, the amount of projection of the move andstop switching slope 75 in the negative X-axis direction at a positionto which the contact plate hooking face 94 contacts continuouslydecreases and the amount of projection of the trailing end contact plate90 to the fence body frame 61 continuously increases. Then, when thereleasing button 70 slides to the fixed state, the trailing end contactplate 90 has fully been projected to the fence body frame 61.

As described above, by finishing the movement of the fixing claw 80 tothe fixing position before the trailing end contact plate 90 hascompletely projected to the fence body frame 61, the positionaldeviation of the end fence 60 to the tray housing 301 due to aprojecting force of the trailing end contact plate 90 is restrained.

When the releasing button 70 slides from the released state to the fixedstate and the fixing claw 80 is moved from the releasing position to thefixing position, it is preferable that the regulated state in which thetrailing end contact plate 90 is regulated from moving is started tochange to the movable state in which the trailing end contact plate 90is movable, after the fixing claw 80 has started moving. Similarly, whenthe releasing button 70 slides from the fixed state to the releasedstate and the fixing claw 80 is moved from the fixing position to thereleasing position, it is preferable that the movable state in which thetrailing end contact plate 90 is movable is started to change to theregulated state in which the trailing end contact plate 90 is regulatedfrom moving, before the fixing claw 80 has started moving.

The above-described configuration is achieved by providing a flatportion parallel to a plane Y-Z on the right side of the move and stopswitching slope 75 in FIG. 1, and by causing the contact plate hookingface 94 to contact the flat portion when the releasing button 70 is neara position at which the releasing button 70 becomes the released state.

In this configuration, as the releasing button 70 starts to slide fromthe released state to the fixed state, the fixing claw upper end portion83 is lowered along the releasing slope 73 and the fixing claw 80 at thereleasing position starts to move toward the fixing position. Bycontrast, the portion to which the contact plate hooking face 94contacts slides on the flat portion as the releasing button 70 startedto slide, and therefore there is no amount of projection of the portionto which the contact plate hooking face 94 contacts in the negativeX-axis direction, in other words, the portion to which the contact platehooking face 94 contacts is not projected in the negative X-axisdirection. Therefore, no operation to switch to a state in which thetrailing end contact plate 90 becomes movable is started. Thereafter,the portion to which the contact plate hooking face 94 contactscorresponds to the move and stop switching slope 75. Therefore, as thecontact plate hooking face 94 starts to move in the positive X-axisdirection along the move and stop switching slope 75, the operation toswitch to the state in which the trailing end contact plate 90 ismovable by application of the biasing force is started.

Accordingly, when the fixing claw 80 moves from the releasing positionto the fixing position, the operation to switch from the state in whichthe trailing end contact plate 90 is regulated from moving to the statein which the trailing end contact plate 90 is movable, after the fixingclaw 80 is started to move.

At the initial stage when the releasing button 70 is started to slidefrom the fixed state to the released state, the portion to which thefixing claw upper end portion 83 contacts slides along the fixing slideplane 78 and the fixing claw 80 at the fixing position is not started tomove to the releasing position. Thereafter, when the portion to whichthe fixing claw upper end portion 83 contacts reaches the releasingslope 73, the fixing claw upper end portion 83 is moved upwardly alongthe releasing slope 73, and the fixing claw 80 is started to move to thereleasing position.

By contrast, as the releasing button 70 starts to slide to the releasedstate, the portion to which the contact plate hooking face 94 contactsis started to move in the negative X-axis direction along the move andstop switching slope 75, and the operation to switch to the regulatedstate in which the trailing end contact plate 90 is regulated frommoving by application of the biasing force is started.

Accordingly, when the fixing claw 80 moves from the fixing position tothe releasing position, the operation to switch from the movable statein which the trailing end contact plate 90 is movable to the regulatedstate in which the trailing end contact plate 90 is regulated frommoving, before the fixing claw 80 is started to move.

With the above-described configuration, the pressing force is generatedwhen the trailing end contact plate 90 presses the trailing end of thesheet P by the biasing force of the contact plate biasing spring 91, andthe end fence 60 is moved to the upstream side of the sheet conveyingdirection due to the reaction force against the pressing force.Accordingly, the end fence 60 is prevented from shifting to generate thepositional deviation of the end fence 60 on the bottom face 301 a.

When the releasing button 70 slides and the fixing claw 80 is moved fromthe releasing position to the fixing position, it is preferable that theoperation to switch from the regulated state in which the trailing endcontact plate 90 is regulated from moving to the movable state in whichthe trailing end contact plate 90 is movable is started after the fixingclaw 80 is moved to the fixing position. Similarly, when the releasingbutton 70 slides and the fixing claw 80 is moved from the fixingposition to the releasing position, it is preferable that the operationto switch from the movable state in which the trailing end contact plate90 is movable to the regulated state in which the trailing end contactplate 90 is regulated from moving is started before the fixing claw 80is started to move.

The above-described configuration is achieved by the following setting.

Specifically, a flat portion parallel to the plane Y-Z is provided onthe right side of the move and stop switching slope 75 in FIG. 1. Then,the length of the flat portion in the Y-axis direction is set to belonger or greater than the length of the releasing slope 73 in theY-axis direction. According to this setting, while the releasing button70 is sliding within a range that the fixing claw upper end portion 83contacts the releasing slope 73, the contact plate hooking face 94remains in contact with the flat portion. Accordingly, while the fixingclaw 80 is moving, the position of the contact plate hooking face 94 inthe X-axis direction does not vary, and therefore the operation toswitch from the regulated state in which the trailing end contact plate90 is regulated from moving to the movable state in which the trailingend contact plate 90 is movable is not performed.

According to the above-described setting, while the releasing button 70is sliding within a range that the fixing claw upper end portion 83contacts the fixing slide plane 78, in other words, in the state inwhich the fixing claw 80 is located at the fixing position, the contactplate hooking face 94 faces the move and stop switching slope 75. Then,as a position of the move and stop switching slope 75 at which thecontact plate hooking face 94 faces varies, the operation to switch fromthe regulated state in which the trailing end contact plate 90 isregulated from moving to the movable state in which the trailing endcontact plate 90 is movable is performed.

In this configuration, it is that the fixing claw 80 is located at thefixing position when the trailing end contact plate 90 is movable by thebiasing force. Specifically, as the pressing to the releasing button 70is cancelled, the end fence 60 is fixed by the fixing claw 80, and thenthe trailing end contact plate 90 becomes rotatable in the directionindicated by arrow D1 in FIG. 17. According to this configuration, bythe reaction force against the pressing force applied when the trailingend contact plate 90 presses the trailing end of the sheet P by thebiasing force of the contact plate biasing spring 91, the end fence 60is prevented from moving on the bottom face 301 a.

The sheet feed tray 30 that functions as a sheet loading deviceaccording to the present embodiment includes the tray housing 301 onwhich the sheet P to be fed to the image forming device 400 is loaded,and the end fence 60. Since the end fence 60 includes the fixing claw 80and the releasing button 70 and the releasing button 70 has a functionas a contact body, the position of the sheet P loaded on the bottom face301 a of the tray housing 301 is stabilized.

Further, the sheet feeding device 300 according to the presentembodiment includes the sheet feed tray 30 and the sheet feed roller 47.Since the end fence 60 provided to the sheet feed tray 30 includes thefixing claw 80 and the releasing button 70 and the releasing button 70has a function as a contact body, the position of the sheet P on thesheet feed tray 30 is stabilized, and a stable sheet feeding isachieved.

Further, the image forming apparatus 100 according to the presentembodiment includes the image forming device 400 and the sheet feedingdevice 300. Since the end fence 60 provided to the sheet feed tray 30 ofthe sheet feeding device 300 includes the fixing claw 80 and thereleasing button 70 and the releasing button 70 has a function as acontact body, a stable sheet feeding is achieved, and therefore thetiming to feed the sheet P to the secondary transfer nip region isstabilized. Accordingly, defect such as the positional deviation of animage is prevented, and therefore the stable image formation isachieved.

In the present embodiment, the trailing end contact plate 90 is moved tothe upstream side of the sheet conveying direction against the biasingforce of the fixing claw biasing spring 81 by causing the position ofthe move and stop switching slope 75 facing the contact plate hookingface 94 to slide. Accordingly, in this configuration, the state isswitched from the movable state in which the trailing end contact plate90 is movable to the regulated state in which the trailing end contactplate 90 is regulated from moving.

To switch the state between the movable state in which the trailing endcontact plate 90 is movable due to the biasing force of the fixing clawbiasing spring 81 and the regulated state in which the trailing endcontact plate 90 is regulated from moving, the following configurationmay also be applied to this disclosure. Specifically, in theconfiguration, a biased state in which the biasing force of the fixingclaw biasing spring 81 is applied to the trailing end contact plate 90and a non-biased state in which the biasing force of the fixing clawbiasing spring 81 is not applied to the fixing claw biasing spring 81.

In the present embodiment, the description was given of the case inwhich a sheet end position regulator that includes a fixing body and acontact body corresponds to the end fence 60 that is movable in thesheet conveying direction. The sheet end position regulating deviceaccording to this disclosure is not limited to the end fence 60. Forexample, a side fence that is movable in a direction perpendicular tothe sheet conveying direction is also applicable as the sheet endposition regulating device to this disclosure.

Further, in the above-described embodiments and examples, thedescription was given of the case where the sheet loader to which thesheet end position regulating device is movably attached corresponds tothe bottom face 301 a of the tray housing 301 of a housing type whoseside is covered with a wall or walls. However, the configurationincluding a sheet loader to which a sheet end position regulating deviceaccording to this disclosure is attached is not limited to theabove-described housing type. For example, a configuration in which anend fence and a side fence or fences are mounted on a planar tray thatforms a sheet loader may be applied.

The configurations according to the above-descried embodiments are notlimited thereto. This disclosure can achieve the following aspectseffectively.

Aspect 1

In Aspect 1, a sheet end position regulating device (for example, theend fence 60) includes a first contact body (for example, the trailingend contact plate 90) disposed movable on a sheet loading portion (forexample, the bottom face 301 a) on which a sheet (for example, the sheetP) is loaded and configured to contact an end portion of the sheet, afixing body (for example, the fixing claw 80) disposed movable between afixing position at which a position of the first contact body to thesheet loading portion is fixed and a releasing position at which theposition of the first contact body is released, and a second contactbody (for example, the releasing button 70) disposed movable between acontact position at which the fixing body contacts a contact targetportion (for example, fixing claw upper end portion 83) to regulatemovement of the fixing body form the fixing position to the releasingposition and a non-contact position at which the fixing body does notcontact the contact target portion.

In a case in which a large impact is applied to the sheet loader towhich the sheet end position regulating device is disposed, a force tomove the fixing body at the fixing position to the releasing positionmay be applied.

In a comparative configuration in which the biasing body restrains themovement of the fixing body from the fixing position to the releasingposition, when the force applied to the fixing body to move to thereleasing position is greater than the biasing force of the biasingbody, the fixing body is moved to the releasing position, and thereforethe position of the fixing body relative to the sheet loader varies.

In Aspect 1, the fixing body is regulated from moving to the releasingposition by the causing the contact body to contact the fixing body.Therefore, even if the force is applied to the fixing body at the fixingposition to move toward the releasing position, the fixing body isprevented from moving to the releasing position. Therefore, the positionof the sheet end position regulating device to the sheet loader is notvaried at an intentional timing, for example, even if a large impact isapplied to the sheet loader.

Aspect 2

In Aspect 1, the sheet end position regulating device further includes areleasing body (for example, the releasing slope 73) configured to causethe fixing body to move from the fixing position to the releasingposition. The releasing body is configured to move along with movementof the second contact body from the contact position to the non-contactposition and cause the fixing body to move from the fixing position tothe releasing position.

According to this configuration, as described in the above embodiment,the releasing body is operated along with the operation of the secondcontact body. Accordingly, the operability is enhanced.

Aspect 3

In Aspect 2, the second contact body is configured to cause the fixingbody from moving to the releasing position when the fixing body islocated at the fixing position. The second contact body moves to thenon-contact position immediately before the releasing body causes thefixing body to move the releasing position.

According to this configuration, as described in the above embodiment,it is prevented that the fixing body moves to the releasing position atthe unintentional timing immediately before the fixing body is moved tothe releasing position by the releasing body.

Aspect 4

In any one of Aspects 1 through 3, the sheet end position regulatingdevice further includes a biasing body (for example, the contact platebiasing spring 91) configured to apply a biasing force and bias thefirst contact body toward an end of the sheet, and a switching body (forexample, the move and stop switching slope 75) configured to switch thebiasing force applied by the biasing body between a force applying statein which the biasing force of the biasing body is applied to the end ofthe sheet via the first contact body and a force suspending state inwhich the biasing force of the biasing body is not applied to the end ofthe sheet via the first contact body. The switching body is configuredto switch the force applying state and the force suspending state alongwith movement of the fixing body.

According to this configuration, as described in the above embodiment,the switching body switches the state to the force suspending state, sothat the sheet end position regulating device is easily set to the sheetbundle of sheets P loaded on the sheet loader at an appropriatepositional relation, and therefore an erroneous setting is prevented.

In addition, the switching body switches the state between the forceapplying state and the force suspending state by moving along withmovement of the fixing body, and therefore the operability is enhanced.

Aspect 5

In Aspect 4, the switching body is in the force applying state when thefixing body is located at the fixing position and the switching body isin the force suspending state when the fixing body is located at thereleasing position.

According to this configuration, as described in the above embodiment,when the fixing body is located at the releasing position and the sheetend position regulating device is movable, by changing the state to theforce suspending state, the position of the sheet end positionregulating device due to the biasing force of the biasing body isrestrained from being shifted.

Aspect 6

In Aspect 5, when the fixing body moves from the releasing position tothe fixing position, the switching body starts switching to the forceapplying state after the fixing body has started to move, and when thefixing body moves from the fixing position to the releasing position,the switching body starts switching to the force suspending state beforethe fixing body starts to move.

According to this configuration, as described in the above embodiment,when the biasing body biases the end portion of the sheet via the firstcontact body, the fixing body is set to the fixing position, and whenthe fixing body is located at the releasing position, it is preventedthat the biasing force of the biasing body is applied to the end portionof the sheet. Therefore, by the reaction force when the biasing bodyapplies the biasing force to the end portion of the sheet via thecontact portion in the force applying state, the position of the sheetend position regulating device with respect to the sheet loader isrestrained from being shifted.

Aspect 7

In any one of Aspects 1 through 3, the sheet end position regulatingdevice further includes a biasing body (for example, the contact platebiasing spring 91) configured to apply a biasing force and bias thefirst contact body toward an end of the sheet, and a switching body (forexample, the move and stop switching slope 75) configured to switch theposition of the first contact body between a first state in which thebiasing force of the biasing body causes the first contact body to movetoward the end portion of the sheet away from a given position and asecond state in which the first contact body is regulated from beingmoved, by the biasing force of the biasing body, toward the end portionof the sheet away from the given position, along with movement of thefixing body.

According to this configuration, as described in the above embodiment,the switching body switches the state to the second state, so that thesheet end position regulating device is easily set to the sheet bundleof sheets P loaded on the sheet loader at an appropriate positionalrelation, and therefore an erroneous setting is prevented.

In addition, the switching body switches the state between the forceapplying state and the force suspending state by moving along withmovement of the fixing body, and therefore the operability is enhanced.

Aspect 8

In Aspect 7, the switching body is in the first state when the fixingbody is located at the fixing position, and the switching body is in thesecond state when the fixing body is located at the releasing position.

According to this configuration, as described in the above embodiment,when the fixing body is located at the releasing position and the sheetend position regulating device is movable, the state is in the secondstate in which the first contact body is prevented from moving due tothe biasing force of the biasing body.

Accordingly, the shift of the position of the sheet end positionregulating device due to the biasing force of the biasing body isrestrained.

Aspect 9

In Aspect 8, when the fixing body moves from the releasing position tothe fixing position, the switching body starts switching to the firststate after the fixing body has started to move, and when the fixingbody moves from the fixing position to the releasing position, theswitching body starts switching to the second state before the fixingbody starts to move.

According to this configuration, as described in the above embodiment,when the state is changed to the first state in which the first contactbody is movable due to the biasing force of the biasing body, the fixingbody is set to be located at the fixing position. Therefore, when thefixing body is located at the releasing position, the first contact bodyis moved by the biasing force of the biasing body, so that it isprevented that the first contact body presses the end of the sheet.Therefore, by the reaction force against the force by which the firstcontact body that is movable in the first state presses the end portionof the sheet, the position of the sheet end position regulating devicewith respect to the sheet loader is restrained from being shifted.

Aspect 10

In Aspect 10, a sheet end position regulating device (for example, theend fence 60) includes a first contact body (for example, the trailingend contact plate 90) disposed movable on a sheet loading portion (forexample, the bottom face 301 a) on which a sheet (for example, the sheetP) is loaded and configured to contact an end portion of the sheet, afixing body (for example, the fixing claw 80) disposed movable between afixing position at which a position of the first contact body to thesheet loading portion is fixed and a releasing position at which theposition of the first contact body is released, a biasing body (forexample, the contact plate biasing spring 91) configured to apply abiasing force and bias the first contact body toward an end of thesheet, and a switching body (for example, the move and stop switchingslope 75) configured to switch the biasing force applied by the biasingbody between a force applying state in which the biasing force of thebiasing body is applied to the end of the sheet via the first contactbody and a force suspending state in which the biasing force of thebiasing body is not applied to the end of the sheet via the firstcontact body. The switching body starts to switch to the force applyingstate after the fixing body has started to move when the fixing bodymoves from the releasing position to the fixing position. The switchingbody starts to switch to the force suspending state before the fixingbody starts to move when the fixing body moves from the fixing positionto the releasing position.

According to this configuration, as described in the above embodiment,when the biasing body biases the end portion of the sheet via the firstcontact body, the fixing body is set to the fixing position, and whenthe fixing body is located at the releasing position, it is preventedthat the biasing force of the biasing body is applied to the end portionof the sheet. Therefore, by the reaction force when the biasing bodyapplies the biasing force to the end portion of the sheet via thecontact portion in the force applying state, the position of the sheetend position regulating device with respect to the sheet loader isrestrained from being shifted.

Aspect 11

In Aspect 6 or Aspect 10, the switching body starts to switch to theforce applying state after the fixing body has moved to the fixingposition when the fixing body moves from the releasing position to thefixing position, and the switching body ends switching to the forcesuspending state before the fixing body starts to move when the fixingbody moves from the fixing position to the releasing position.

According to this configuration, as described in the above embodiment,by the reaction force against the force by which the first contact bodypresses the end portion of the sheet in the force applying state, theposition of the sheet end position regulating device with respect to thesheet loader is prevented from being shifted.

Aspect 12

In Aspect 9, when the fixing body moves from the releasing position tothe fixing position, the switching body starts switching to the firststate after the fixing body has moved to the fixing position, and whenthe fixing body moves from the fixing position to the releasingposition, the switching body ends switching to the second state beforethe fixing body starts to move.

According to this configuration, as described in the above-describedembodiment, by the reaction force against the force by which the firstcontact body that is movable presses the end portion of the sheet in thefirst state, the position of the sheet end position regulating devicewith respect to the sheet loader is prevented from being shifted.

Aspect 13

A sheet loader (for example, the sheet feed tray 30) includes a sheetloading portion (for example, the bottom face 301 a) on which a sheet(for example, the sheet P) is loaded, and the sheet end positionregulating device (for example, the end fence 60) of Aspect 1, disposedmovable to the sheet loading portion and configured to regulate an endportion of the sheet loaded on the sheet loading portion.

According to this configuration, as described in the above embodiment,the position of the sheet on the sheet loader is stabilized.

Aspect 14

A sheet feeder (for example, the sheet feeding device 300) includes thesheet loader (for example, the sheet feed tray 30) of Aspect 13, onwhich a sheet (for example, the sheet P) is loaded, and a sheet feedingbody (for example, the sheet feed roller 47) configured to feed thesheet loaded on the sheet loader.

According to this configuration, as described in the above embodiment,the position of the sheet on the sheet loading portion of the sheetloader is stabilized, and therefore a stable sheet feeding operation isachieved.

Aspect 15

In Aspect 15, an image forming device (for example, the image formingdevice 400) configured to form an image on a sheet (for example, thesheet P), and the sheet feeder (for example, the sheet feeding device300) of Aspect 14, configured to feed the sheet toward the image formingdevice.

According to this configuration, as described in the above embodiment, astable sheet feeding operation is performed, and therefore a defect suchas a positional deviation of an image is prevented, so that a stableimage forming operation is performed.

The above-described embodiments are illustrative and do not limit thisdisclosure. Thus, numerous additional modifications and variations arepossible in light of the above teachings. For example, elements at leastone of features of different illustrative and exemplary embodimentsherein may be combined with each other at least one of substituted foreach other within the scope of this disclosure and appended claims.Further, features of components of the embodiments, such as the number,the position, and the shape are not limited the embodiments and thus maybe preferably set. It is therefore to be understood that within thescope of the appended claims, the disclosure of this disclosure may bepracticed otherwise than as specifically described herein.

What is claimed is:
 1. A sheet end position regulating devicecomprising: a first contact body on an end face of the sheet endposition regulating device and disposed movable toward a sheet loadingportion on which a sheet is loaded and configured to contact an endportion of the sheet; a fixing body movable in to and out of the sheetend position regulating device between a fixing position at which aposition of the first contact body to the sheet loading portion is fixedand a releasing position at which the position of the first contact bodyis released; and a second contact body movable in to and out of thesheet end position regulating device between a contact position at whichthe fixing body contacts a portion of the second contact body toregulate movement of the fixing body from the fixing position to thereleasing position and a non-contact position at which the fixing bodydoes not contact the portion of the second contact body, the secondcontact body having a first wedge shaped portion slidably engageablewith the fixing body and a second wedge shaped portion slidablyengageable with the first contact body, wherein the second contact bodyis movable in a direction perpendicular to a moving direction of thesheet end position regulating device and the fixing body is movableperpendicular to the moving direction of the second contact body.
 2. Thesheet end position regulating device according to claim 1, wherein thefirst wedge shaped portion is a releasing body configured to cause thefixing body to move from the fixing position to the releasing position,wherein the second contact body includes the releasing body configuredto move along with movement of the second contact body from the contactposition to the non-contact position and engage with the fixing body andcause the fixing body to move from the fixing position to the releasingposition.
 3. The sheet end position regulating device according to claim2, wherein the second contact body is configured to regulate the fixingbody from moving to the releasing position when the fixing body islocated at the fixing position, and wherein the second contact bodymoves to the non-contact position immediately before the releasing bodycauses the fixing body to move to the releasing position.
 4. The sheetend position regulating device according to claim 1, further comprising;a biasing body in contact with the first contact body and configured toapply a biasing force and bias the first contact body toward the endportion of the sheet, wherein the second contact body includes aswitching body configured to switch the biasing force applied by thebiasing body between a force applying state in which the biasing forceof the biasing body is applied to the end portion of the sheet via thefirst contact body and a force suspending state in which the biasingforce of the biasing body is not applied to the end portion of the sheetvia the first contact body, wherein the switching body is configured toswitch the force applying state and the force suspending state alongwith movement of the fixing body.
 5. The sheet end position regulatingdevice according to claim 4, wherein the switching body is in the forceapplying state when the fixing body is located at the fixing position,and wherein the switching body is in the force suspending state when thefixing body is located at the releasing position.
 6. The sheet endposition regulating device according to claim 5, wherein, when thefixing body moves from the releasing position to the fixing position,the switching body starts switching to the force applying state afterthe fixing body has started to move, and wherein, when the fixing bodymoves from the fixing position to the releasing position, the switchingbody starts switching to the force suspending state before the fixingbody starts to move.
 7. The sheet end position regulating deviceaccording to claim 6, wherein the switching body starts to switch to theforce applying state after the fixing body has moved to the fixingposition when the fixing body moves from the releasing position to thefixing position, and wherein the switching body ends switching to theforce suspending state before the fixing body starts to move when thefixing body moves from the fixing position to the releasing position. 8.The sheet end position regulating device according to claim 1, furthercomprising: a biasing body in contact with the first contact body andconfigured to apply a biasing force and bias the first contact bodytoward the end portion of the sheet, wherein a switching body isconfigured to switch the position of the first contact body between afirst state in which the biasing force of the biasing body causes thefirst contact body to move toward the end portion of the sheet away froma given position and a second state in which the first contact body isregulated from being moved, by the biasing force of the biasing body,toward the end portion of the sheet away from the given position, alongwith movement of the fixing body.
 9. The sheet end position regulatingdevice according to claim 8, wherein the switching body is in the firststate when the fixing body is located at the fixing position, andwherein the switching body is in the second state when the fixing bodyis located at the releasing position.
 10. The sheet end positionregulating device according to claim 9, wherein, when the fixing bodymoves from the releasing position to the fixing position, the switchingbody starts switching to the first state after the fixing body hasstarted to move, and wherein, when the fixing body moves from the fixingposition to the releasing position, the switching body starts switchingto the second state before the fixing body starts to move.
 11. The sheetend position regulating device according to claim 10, wherein, when thefixing body moves from the releasing position to the fixing position,the switching body starts switching to the first state after the fixingbody has moved to the fixing position, and wherein, when the fixing bodymoves from the fixing position to the releasing position, the switchingbody ends switching to the second state before the fixing body starts tomove.
 12. A sheet loader comprising: the sheet loading portion on whichthe sheet is loaded; and the sheet end position regulating deviceaccording to claim 1, disposed movable to the sheet loading portion andconfigured to regulate the end portion of the sheet loaded on the sheetloading portion.
 13. A sheet feeder comprising: the sheet loaderaccording to claim 12, on which the sheet is loaded; and a sheet feedingbody configured to feed the sheet loaded on the sheet loader.
 14. Animage forming apparatus comprising: an image forming device configuredto form an image on a sheet; and the sheet feeder according to claim 13,configured to feed the sheet toward the image forming device.
 15. Thesheet end position regulating device according to claim 1, wherein thesecond contact body is movable into and out of the sheet end positionregulating device in a direction orthogonal to a sheet conveyingdirection and parallel to the sheet loading portion, and the portion ofthe second contact body varies in thickness.
 16. A sheet end positionregulating device comprising: a first contact body disposed movabletoward a sheet loading portion on which a sheet is loaded and configuredto contact an end portion of the sheet; a fixing body disposed movablebetween a fixing position at which a position of the first contact bodyto the sheet loading portion is fixed and a releasing position at whichthe position of the first contact body is released; a biasing bodyconfigured to apply a biasing force and bias the first contact bodytoward the end portion of the sheet; and a switching body movable in toand out of the sheet end position regulating device in a directionorthogonal to a sheet conveying direction and parallel to the sheetloading portion, and configured to switch the biasing force applied bythe biasing body between a force applying state in which the biasingforce of the biasing body is applied to the end portion of the sheet viathe first contact body and a force suspending state in which the biasingforce of the biasing body is not applied to the end portion of the sheetvia the first contact body, the switching body configured to start toswitch to the force applying state after the fixing body has started tomove when the fixing body moves from the releasing position to thefixing position, the switching body having a first wedge shaped portionslidably engageable with the fixing body and a second wedge shapedportion slidably engageable with the first contact body and configuredto start to switch to the force suspending state before the fixing bodystarts to move when the fixing body moves from the fixing position tothe releasing position.
 17. The sheet end position regulating deviceaccording to claim 16, wherein the switching body starts to switch tothe force applying state after the fixing body has moved to the fixingposition when the fixing body moves from the releasing position to thefixing position, and wherein the switching body ends switching to theforce suspending state before the fixing body starts to move when thefixing body moves from the fixing position to the releasing position.18. A sheet loader comprising: the sheet loading portion on which thesheet is loaded; and the sheet end position regulating device accordingto claim 16, disposed movable to the sheet loading portion andconfigured to regulate an end portion of the sheet loaded on the sheetloading portion.
 19. A sheet feeder comprising: the sheet loaderaccording to claim 18, on which the sheet is loaded; and a sheet feedingbody configured to feed the sheet loaded on the sheet loader.
 20. Animage forming apparatus comprising: an image forming device configuredto form an image on a sheet; and the sheet feeder according to claim 19,configured to feed the sheet toward the image forming device.